At present, a subscriber to a telephone service may use an automatic answering machine, which may or may not be designed to record a message from a calling party, or use an answering service. The subscriber may also use a call forwarding feature offered by the local telephone company which automatically routes incoming calls to a different telephone number.
Answering services and telephone company call forwarding features are not available everywhere and, where available, require the periodic payment of a fee for that service or feature. Furthermore, automatic answering machines and telephone company call forwarding features must be activated and deactivated at the subscriber's telephone set and cannot be remotely activated or deactivated. If a subscriber has the use of a call forwarding feature and plans to be at two or more different locations during the day he must either return to his office between every different location or resign himself to having some of his calls forwarded to a first location (to which the calls are routed) while he is at the second location.
Furthermore, he must return to his office to cancel the call forwarding feature. The subscriber must also return to his office if he wishes to change from automatic answer to call forward, or vice versa. These limitations are a major inconvenience to a busy subscriber whose time is valuable and cannot be wasted on making numerous return trips to his office. Under these conditions, the utility of conventional call forward service is limited.
Thus, there is a need for an improvement in telephone answering and call forwarding apparatus which will allow for remote activation, modification, and deactivation of an automatic answering device and the call forwarding service provided by central office equipment.
Conventional devices which transmit or receive information over telephone lines have one or more transformers to isolate the telephone line from grounding by the device. Transformers often significantly increase the size, weight and cost of the devices in which they are used. Transformers also have a limited bandwidth, do not pass direct current, and therefore limit the amount of information that may be obtained from the telephone line. There is, therefore, a need for a device which can transmit and receive information over telephone lines without transformers but which does not ground the telephone line.